This is always nice to use in other distros - all the multimedia LiveCD's have RT as standard - makes their distros very snappy and slick to use.

Why not Kanotix?? What is the downside?

brodders

slh

Titel: RE: Realtime kernel Verfasst am: 27.09.2006, 18:03 Uhr

Anmeldung: 16. Aug 2004
Beiträge: 1905

What do YOU expect from a realtime kernel?

--
(hint, realtime degrades performance significantly)

brodders

Titel:Verfasst am: 28.09.2006, 17:52 Uhr

Anmeldung: 15. Jan 2005
Beiträge: 107

Hi,

my understanding the RT kernel is to minimise delays - typically for audio / multimedia apps, which need (?why - what's wrong with buffering?) instant responses. The patches tweek the schedular and insert more I/O event task checking in blocks of code which would otherwise hog time (so delaying response).

Why do I like RT distros? Well, using say dyna:bolic it is very clear that the RT mods make the system extremely smooth in use.

That's it. I like the responsive feel of <it's done> over <..it's done> !

No functional benefit - except the feel of using the distro. It's better.

So I wonder - why not ship as standard like this - what is the downside?

brodders

mzilikazi

Titel:Verfasst am: 28.09.2006, 18:21 Uhr

Team Member

Anmeldung: 17. Dez 2003
Beiträge: 1109
Wohnort: Ganymede

The rt patches don't cause any noticible speed improvement here but I do use an rt kernel for my audio applications e.g. Ardour, XMMS, etc. It's quite simple to build your own rt kernel and there is even a Howto for your reading enjoyment. In case you did not notice Kanotix is not billed as a multimedia distro.

--
I'm honestly interested in your answer or different definitions for the majority of kanotix users.

Cathbard

Titel:Verfasst am: 30.09.2006, 14:14 Uhr

Artist

Anmeldung: 11. Aug 2005
Beiträge: 451
Wohnort: Australia

I use a RT kernel because I use Ardour, Muse etc so I just compile it myself. What would be nice however is an option to patch the kernel with RT in H2's script. Hint hint
Recording apps in linux are brilliant but patching the kernel for RT often scares people away which is a shame. A script would be nice.

Why would we blindly introduce an intricate, invasive patch that significant modifies core behaviours of the kernel just so a smal subset of the population may feel as if they now have an advantage when using their audio apps?

Best wait until the guru's (linux kernel maintainers) integrate this functionality in the future.

What would be nice however is an option to patch the kernel with RT in H2's script.

Better yet would be an rt kernel ready to download & install. I *may* put an effort to that end in the near future. 2.6.18-rt3 honestly did not work so well and I dropped back to 2.6.17-rt Now that patch-2.6.18-rt5 is out I need to recompile and test for a while.

If it wasnt absoultely necessary to patch the kernel to acheive decent audio latencies then we surely wouldnt all bother? And those of us who use serious auidio apps thank mzilikazi for his excellent how to- which recieves decent interest to this date- and acheives RT kernel within less than 10 mins. Of course Kano is no musician (to my knowledge anyway lol) and this is HIS distro, so we wont be seeing an RT kernel ship with kanotix- it would be a waste of (valuable) disk space.

_________________Linux user 403389 and Herbaholic Trichopath

Cathbard

Titel:Verfasst am: 04.10.2006, 22:21 Uhr

Artist

Anmeldung: 11. Aug 2005
Beiträge: 451
Wohnort: Australia

An RT kernel shipped in the iso wouldn't even be on the wish list. That would have to be a private DAW project of some sort. However, looking forward to MZ's kernel packages, thats the way to do it. Nice one.

If someone creates a rt kernel that is fully compatible with the install directions for kanotix standard kernels it's no problem to add that option to du-fixes, but only if the kernel package is 100% compatible with the standard kanotix formats.

thanks a lot for this, so many musician can see the real performens from jackd ardur rosegarden ..... without compile a one kernel
i put a link in german forum for that
i enjoy it

mzilikazi

Titel:Verfasst am: 09.10.2006, 21:32 Uhr

Team Member

Anmeldung: 17. Dez 2003
Beiträge: 1109
Wohnort: Ganymede

OK made a few changes:
Added PAM module to zip archive.
The install-realtime-kernel.sh will install the PAM module for you.
Small fix for stupid error in mz-source.sh
Moved rt5 patch to a different mirror. When ingo uploads a new patch the old one is removed!
This would not work too well for building a realtime patched kernl source.

Just tested the install-realtime-kernel.sh, mz-source.sh on a fresh RC4 installation. It works fabulously.

mzilikazi, you might want to disable wlan and ISDN driver (and some others on a case by case basis) completely because both introduce long non interruptable latencies - one of the reasons why -rt kernels (besides their own problems) aren't usable for general purpose systems, just like -rt patched kernels with a generic configuration aren't useful for serious realtime tasks...

Oktyabr

Titel:Verfasst am: 15.10.2006, 20:56 Uhr

Anmeldung: 03. Okt 2006
Beiträge: 6
Wohnort: Washington State, USA

Anyone tried the 2.6.18-1-486 kernel from the Debian unstable repositories? I've got it running on my RC3 install right now and hitting 5.8msec latency with an onboard nForce4 sound chip and the only xruns I'm getting is when I open a new window (like Firefox to post this)!

Very nice, no hacked pam modules or anything.

mzilikazi

Titel:Verfasst am: 15.10.2006, 23:32 Uhr

Team Member

Anmeldung: 17. Dez 2003
Beiträge: 1109
Wohnort: Ganymede

Oktyabr hat folgendes geschrieben::

the only xruns I'm getting is when I open a new window (like Firefox to post this)!

Very nice, no hacked pam modules or anything.

That is completely unacceptable for music production and the PAM module is not 'hacked'.

Edit
libpam-modules-0.79-4 in Debian testing/sid is perfectly fine for realtime BUT
you must edit /etc/security/limits.conf.
Append the following to the end: